Document Type : Original Article


Ethiopian Environment and Forest Research Institute, Forest Products Innovation Research and Training Center, Addis Ababa, Ethiopia.


The low bulk density of wood wastes causes handling, storage, and transportation issues, limiting its large-scale application. Pelletization can solve this inherent problem by converting biomass into dense and compact pellets with regular shape and size. To evaluate the effect of particle size and binding agents on pellets of carbonized Pinus patula sawdust, the particle size of 0.6 mm, 1.18 mm and 2.3 mm and binding agents of cow dung, molasses and wastepaper were used. The experimental results indicated that the addition of cow dung and molasses into the carbonized sawdust resulted in increase of calorific value, decrease of ash content and increase of fixed carbon. As a result, the maximum calorific value of 28.47 MJ/kg, ash content of 2.93%, and fixed carbon of 59.32% were obtained by using molasses.The calorific value of 25.8 MJ/kg, ash content of 6.03% and fixed carbon of 52.77% were obtained by using cow dung. Whereas, addition of wastepaper into carbonized sawdust resulted in lower calorific value of 22.3 MJ/kg, highest ash value of 8.35% and low fixed carbon of 43.2%. Therefore, the use of cow dung and molasses as a binder can be considered as a sustainable approach to improve the physicochemical properties of biomass pellets.


Main Subjects

[1] I. Ahmed et al., “Socio-Economic and Environmental Impacts of Biomass Valorisation: A Strategic Drive for Sustainable Bioeconomy,” Sustainability, Vol. 13, No. 8, p. 4200, Apr. 2021, doi: 10.3390/su13084200.
[2] M. Ozturk et al., “Biomass and bioenergy: An overview of the development potential in Turkey and Malaysia,” Renew. Sustain. Energy Rev., Vol. 79, pp. 1285–1302, Nov. 2017, doi: 10.1016/j.rser.2017.05.111.
[3] S. Adhikari and B. Ozarska, “Minimizing environmental impacts of timber products through the production process ‘From Sawmill to Final Products,’” Environ. Syst. Res., Vol. 7, No. 1, p. 6, Dec. 2018, doi: 10.1186/s40068-018-0109-x.
[4] N. Iskandar, S. Sulardjaka, M. Munadi, S. Nugroho, A. S. Nidhom, and D. F. Fitriyana, “The characteristic of bio-pellet made from teak wood waste due to the influence of variations in material composition and compaction pressure,” J. Phys. Conf. Ser., Vol. 1517, No. 1, p. 012017, Apr. 2020, doi: 10.1088/1742-6596/1517/1/012017.
[5] Guta, “Assessment of Biomass Fuel Resource Potential And Utilization in Ethiopia: Sourcing Strategies for Renewable Energies,” 2012.
[6] Jamradloedluk and ct heat deman, “Influences of Mixing Ratios and Binder Types on Properties of Biomass Pellets,” 2017.
[7] N. E. Benti et al., “The current status, challenges and prospects of using biomass energy in Ethiopia,” Biotechnol. Biofuels, Vol. 14, No. 1, p. 209, Dec. 2021, doi: 10.1186/s13068-021-02060-3.
[8] M. Iftikhar, A. Asghar, N. Ramzan, B. Sajjadi, and W. Chen, “Biomass densification: Effect of cow dung on the physicochemical properties of wheat straw and rice husk based biomass pellets,” Biomass Bioenergy, Vol. 122, pp. 1–16, Mar. 2019, doi: 10.1016/j.biombioe.2019.01.005.
[9] A. Akbar, U. Aslam, A. Asghar, and Z. Aslam, “Effect of binding materials on physical and fuel characteristics of bagasse based pellets,” Biomass Bioenergy, Vol. 150, p. 106118, Jul. 2021, doi: 10.1016/j.biombioe.2021.106118.
[10] Global Bioenergy Statistics, “Global bioenergy statistics 2019.” 2019.
[11] A. Harun, “Effect of Particle Size on Mechanical Properties of Pellets Made from Biomass Blends,” 2016.
[12] Y. Huang et al., “Biofuel pellets made at low moisture content–Influence of water in the binding mechanism of densified biomass,” Biomass Bioenergy, Vol. 98, pp. 8–14, Mar. 2017, doi: 10.1016/j.biombioe.2017.01.002.
[13] H. Shahrukh, A. O. Oyedun, A. Kumar, B. Ghiasi, L. Kumar, and S. Sokhansanj, “Techno-economic assessment of pellets produced from steam pretreated biomass feedstock,” Biomass Bioenergy, Vol. 87, pp. 131–143, Apr. 2016, doi: 10.1016/j.biombioe.2016.03.001.
[14] Paulk, “Factors impacting pellet quality,” 2021.
[15] Kpalo, Mohamad Faiz, and Latifah Abd, “Production and Characterization of Hybrid Briquettes from Corncobs and Oil Palm Trunk Bark under a Low Pressure Densification Technique,” 2020.
[16] P. Pradhan, S. M. Mahajani, and A. Arora, “Production and utilization of fuel pellets from biomass: A review,” Fuel Process. Technol., Vol. 181, pp. 215–232, Dec. 2018, doi: 10.1016/j.fuproc.2018.09.021.
[17] M. Younis, S. Y. Alnouri, B. J. Abu Tarboush, and M. N. Ahmad, “Renewable biofuel production from biomass: a review for biomass pelletization, characterization, and thermal conversion techniques,” Int. J. Green Energy, Vol. 15, No. 13, pp. 837–863, Oct. 2018, doi: 10.1080/15435075.2018.1529581.
[18] Y. Si et al., “Effect of Carboxymethyl Cellulose Binder on the Quality of Biomass Pellets,” Energy Fuels, Vol. 30, No. 7, pp. 5799–5808, Jul. 2016, doi: 10.1021/acs.energyfuels.6b00869.
[19] M. Soleimani, X. L. Tabil, R. Grewal, and L. G. Tabil, “Carbohydrates as binders in biomass densification for biochemical and thermochemical processes,” Fuel, Vol. 193, pp. 134–141, Apr. 2017, doi: 10.1016/j.fuel.2016.12.053.
[20] N. Mišljenović, R. Čolović, Đ. Vukmirović, T. Brlek, and C. S. Bringas, “The effects of sugar beet molasses on wheat straw pelleting and pellet quality. A comparative study of pelleting by using a single pellet press and a pilot-scale pellet press,” Fuel Process. Technol., Vol. 144, pp. 220–229, Apr. 2016, doi: 10.1016/j.fuproc.2016.01.001.
[21] A. Amaya, “Preparation of Charcoal Pellets from Eucalyptus Wood with Different Binders,” J. Energy Nat. Resour., Vol. 4, No. 2, p. 34, 2015, doi: 10.11648/j.jenr.20150402.12.
[22] I. Niedziółka et al., “Assessment of the energetic and mechanical properties of pellets produced from agricultural biomass,” Renew. Energy, Vol. 76, pp. 312–317, Apr. 2015, doi: 10.1016/j.renene.2014.11.040.
[23] EN 16126:2012, “Determination of particle size distribution of disintegrated pellets.” 2012.
[24] Zubairu and Gana, “Production and Characterization of Briquette Charcoal by Carbonization of Agro-Waste,” 2015.
[25] Weldemedhin, Alemayehu Haddis, and Esayas Alemayehu, “The Potential of Coffee Husk and Pulp as an Alternative Source of Environmentally Friendly Energy.” 2014.
[26] ASTM D3173-11, “Standard Test Method for Moisture in the Analysis Sample of Coal and Coke.” 2017.
[27] ASTM D3175-18, “Standard Test Method for Volatile Matter in the Analysis Sample of Coal and Coke.” 2018.
[28] ASTM D3174-12(2018), “Standard Test Method for Ash in the Analysis Sample of Coal and Coke from Coal.” 2018.
[29] ASTM D5865-13, “Standard Test Method for Gross Calorific Value of Coal and Coke.” 2019.
[30] ASTM D 3177 – 02, “Standard Test Methods for Total Sulfur in the Analysis Sample of Coal and Coke1.” 2018.
[31] Obidziński, Dołżyńska, and Stasiełuk, “Production of fuel pellets from a mixture of sawdust and rye bran,” 2019.
[32] EN ISO 17225-1:2014, “Solid biofuels - Fuel specifications and classes.” 2014.
[33] T. Wang et al., “Effect of molasses binder on the pelletization of food waste hydrochar for enhanced biofuel pellets production,” Sustain. Chem. Pharm., Vol. 14, p. 100183, Dec. 2019, doi: 10.1016/j.scp.2019.100183.
[34] Prabhakaran, Muruganandhan, Karthikeyan, and Mugilvalavan, “Bio-oil produced from paper waste and paper cup using pyrolysis process,” 2018.
[35] N. D. Choudhury, N. Saha, B. R. Phukan, and R. Kataki, “Characterization and Evaluation of Energy Properties of Pellets produced from Coir pith, Saw dust and Ipomoea carnea and their blends,” Energy Sources Part Recovery Util. Environ. Eff., pp. 1–18, Jan. 2021, doi: 10.1080/15567036.2020.1871446.
[36] G. Komitov, V. Rasheva, and I. Binev, “Methodology for quickly determining the quality of pellets,” Int. Symp. Environ. Ind., No. SIMI 2019, pp. 207–214, Sep. 2019, doi: 10.21698/simi.2019.fp27.
[37] H. M. Desta and C. S. Ambaye, “Determination of Energy Properties of Fuelwood from Five Selected Tree Species in Tropical Highlands of Southeast Ethiopia,” J. Energy, Vol. 2020, pp. 1–7, Mar. 2020, doi: 10.1155/2020/3635094.
[38] Y. Zhai et al., “Production of fuel pellets via hydrothermal carbonization of food waste using molasses as a binder,” Waste Manag., Vol. 77, pp. 185–194, Jul. 2018, doi: 10.1016/j.wasman.2018.05.022.
[39] DIN EN 15270:2008-03, “Pellet burners for small heating boilers - Definitions, requirements, testing, marking.” 2008.
[40] A. Garcia-Maraver, “Factors Affecting Pellet Quality,” in WIT Transactions on State of the Art in Science and Engineering, 1st Ed., Vol. 1, A. Garcia-Maraver and J. A. Perez-Jimenez, Eds. WIT Press, 2015, pp. 21–35. doi: 10.2495/978-1-84566-062-8/002.